The MDS application checks the alternative expression each time the component is modified. if the expression is true, the alternative design parameters to the right of the expression are used. In the example screenshot above, when design parameter 5 is greater than 100mm, design parameter 7 is set to 6mm and design parameter 9 is set to 25mm. This creates stiffeners on the AT01 pipe shoe 6mm thick and located 25mm from each end of the shoe.